This is a utility function we can use to see whether an executable is available. --- util/Makefile.local | 2 +- util/search-path.c | 55 +++++++++++++++++++++++++++++++++++++++++++++++++++++ util/search-path.h | 24 +++++++++++++++++++++++ 3 files changed, 80 insertions(+), 1 deletion(-) create mode 100644 util/search-path.c create mode 100644 util/search-path.h diff --git a/util/Makefile.local b/util/Makefile.local index 905f237..8b2b91b 100644 --- a/util/Makefile.local +++ b/util/Makefile.local @@ -5,7 +5,7 @@ extra_cflags += -I$(srcdir)/$(dir) libutil_c_srcs := $(dir)/xutil.c $(dir)/error_util.c $(dir)/hex-escape.c \ $(dir)/string-util.c $(dir)/talloc-extra.c $(dir)/zlib-extra.c \ - $(dir)/util.c + $(dir)/util.c $(dir)/search-path.c libutil_modules := $(libutil_c_srcs:.c=.o) diff --git a/util/search-path.c b/util/search-path.c new file mode 100644 index 0000000..5eac367 --- /dev/null +++ b/util/search-path.c @@ -0,0 +1,55 @@ +#include "search-path.h" +#include <stdlib.h> +#include <talloc.h> +#include <unistd.h> +#include <string.h> +#include <sys/types.h> +#include <sys/stat.h> +#include <fcntl.h> + + +notmuch_bool_t +test_for_executable(const char* exename) +{ + char *c = NULL, *save = NULL, *tok; + size_t n; + int dfd = -1; + notmuch_bool_t ret = FALSE; + + if (strchr(exename, '/')) { + if (0 == access(exename, X_OK)) + return TRUE; + else + return FALSE; + } + + c = getenv("PATH"); + if (c) + c = talloc_strdup(NULL, c); + else { + n = confstr(_CS_PATH, NULL, 0); + c = (char*)talloc_size(NULL, n); + if (!c) + return FALSE; + confstr(_CS_PATH, c, n); + } + + tok = strtok_r(c, ":", &save); + while (tok) { + dfd = open(tok, O_DIRECTORY | O_RDONLY); + if (dfd != -1) { + if (!faccessat(dfd, exename, X_OK, 0)) { + ret = TRUE; + goto done; + } + close(dfd); + } + tok = strtok_r(NULL, ":", &save); + } +done: + if (dfd != -1) + close(dfd); + if (c) + talloc_free(c); + return ret; +} diff --git a/util/search-path.h b/util/search-path.h new file mode 100644 index 0000000..727d0b3 --- /dev/null +++ b/util/search-path.h @@ -0,0 +1,24 @@ +#ifndef _SEARCH_PATH_H +#define _SEARCH_PATH_H + +#include "notmuch.h" + +/* can an executable be found with the given name? + * + * Return TRUE only if we can find something to execute with the + * associated name. + * + * if the name has a '/' in it, we look for it directly with + * access(exename, X_OK). + * + * otherwise, we look for it in $PATH (or in confstr(_CS_PATH), if + * $PATH is unset). + * + * This should match the logic for execvp (as well as matching user + * expectations, hopefully). + */ + +notmuch_bool_t +test_for_executable(const char *exename); + +#endif -- 2.7.0.rc3